A semiconductor device, such as a chip, is an electrical device integrating many conductive layers. The semiconductor device usually has an alignment mark in a top conductive layer for being aligning with other instruments (for example, a carrier in a tape carrier package process). However, in the conventional semiconductor device, there must be nothing under the alignment mark for avoiding that the identification rate of the alignment mark is influenced. A region of the semiconductor device must be reserved for the layout of the alignment mark, such that the layout of the circuit layer is limited. As a result, the region of the semiconductor device corresponding to the alignment mark can't be used, and the cost of the semiconductor device can't be reduced further.